John s



J. S. ARMSTRONG.

Improvement in Wood-Screws.

N0. 132,946, Patentd Nov.12,1872.

wimwmz gammai f 9 z i 7 5 m AM /{UTO-t/THUGRAFHIC COJLYKGSBOHNES PROCESS UNITED STATES JOHN S. ARMSTRONG, OF ST. JOHN, CANADA.

lMPROVEMENT IN WOOD SCREWS.

Specification forming part of Letters Patent No. 132,945, dated November 12, 1872.

To all whom it may concern:

Be it known that I, JOHN S. ARMSTRONG, of St. John, in the province of New Brunswick and Dominion of Canada, have invented elevation of a screw-driver with a divided blade adapted for wedgin g into the nick from each end, and a handle arranged for forcing the nicks in by being shoved down along the blade after the bits have been entered in the nick.

Similar letters of reference indicate corresponding parts.

A represents the head of the screw with a transverse nick, B, in the top which tapers from each end to the center 0, so that the blade of a screw-driyer shaped in cross-section to correspond with the shape of the nick and made suitably thick to fill the nick properly cannot slip out of the nick at the ends, as ordinary screw-drivers do. This nick is also under out or dovetailshaped in cross-section,

for fastening the screw on the end of the screw-driver when the blade is made of two parts, D, for being wedged into the nick from each end toward the center, to facilitate the presenting screws to the wood overhead or in other places where it is difficult to reach with one hand to hold the screw and the other to hold the driver 5 thus the driver becomes an instrument for holding and presenting the screw while performing its special function of driving it.

The driver represented in the drawing with two bits for wedging into the nick from the ends toward the middle is arranged for so wed gin g them in by forcing the handle E down along the curved edges of the blades; but other cont-rivances'can be made for so wedging the bits into the nick.

Having thus described my invention, I claim as new and desire to secure by Letters Patent- A screw provided with nick B B widening from the center toward the circumference, to allow the edge of driver to be pressed up and wedged tightly near the center, as set forth.

JOHN SIMEON ARMSTRONG.

VVitne-sses:

J. R. ARMSTRONG, W. H. G. J ONES. 

